This invention relates to a power transmission device for an inboard/outboard drive system and more particularly to an improved, compact and efficient drive arrangement for an outboard drive system.
Many common forms of outboard drives for watercraft employ a horizontally extending input shaft that extends through the transom of the watercraft and which forms the input for the outboard drive. Some form of transmission drives a vertically extending drive shaft from the horizontally extending input shaft. In many forms, this transmission comprises a forward, reverse transmission that is selectively engaged by a clutching mechanism that is disposed between a pair of axially spaced bevel gears that are journaled on the input shaft and which may be selectively coupled to it for effecting forward or reverse drive of a bevel gear affixed to the upper end of the drive shaft. In some instances, there is also incorporated a change speed transmission at the connection between the input shaft and the drive shaft. Although such arrangements have certain advantages in that they reduce the shock and noise during shifting and can avoid slippage at low speeds, the bulk of the transmission with this type of arrangement limits the amount of tilting up of the outboard drive that is possible.
It is, therefore, a principal object of this invention to provide an improved, compact and yet highly efficient transmission system for an outboard drive.
It is a further object of this invention to provide a transmission system for an outboard drive embodying a rearwardly positioned coupling between the drive shaft and input shaft so as to not interfere with the amount of possible pivotal movement of the outboard drive.